Studies of regeneration in experimental spinal cord repair rarely identify whether the regenerating axons make appropriate connections. Here we aim to characterize specific connections in normal rats, for later comparisons with regenerating axons. Respiratory axons are used to allow definition of functional specificity. Thoracic motoneurones are used as targets so that connections can be readily identified. Importantly, these motoneurones may be contacted by regenerating axons with a minimal regeneration distance after a spinal cord transection. Experiments were made on vagotomized rats anaesthetized with ketamine plus xylazine (induced, I.P., 100mg/kg, 10 mg/kg, respectively, then I.V. as required), or urethane (1.4g/kg, I.P.) or halothane (induced 5%, then as required), or decerebrated under ketamine plus xylazine (as above). Neuromuscular blockade (pancuronium bromide at 0.3mg/hr I.V.) and artificial ventilation were used, with CO₂ added to the inspired gas to enhance the respiratory drive. Adequacy of anaesthesia was assessed by observations of blood pressure and respiratory patterns following noxious paw pinches. Extracellular recordings were made from single expiratory bulbospinal neurones (EBSNs) in the caudal medulla, antidromically identified from T11. Connections from EBSNs to motoneurones were sought either by cross-correlation between EBSN discharges and efferent discharges in contralateral intercostal nerves (T6-T10), or by spike-triggered averaging (STA) to contralateral thoracic motoneurones (intracellular recording, T9-T10). Expiratory discharges occurred in both internal and external intercostal nerves, extending observations of Tian & Duffin (1996). Under anaesthesia, such discharges occurred only when the anaesthesia was light, and were often weak or intermittent. Correlation results to date derive from decerebrate preparations with strong expiratory discharges. Monosynaptic connections have consistently been shown to internal intercostal nerve motoneurones (7/14 EBSNs, 5 animals), using criteria from Kirkwood (1995) related to latencies and durations of peaks in the cross correlation histograms. Monosynaptic connections were not detected to external intercostal nerve motoneurones, but in one animal several EBSNs gave correlation peaks indicative of disynaptic connections and, in another animal, troughs were seen, indicative of di- or trisynaptic inhibition. STA has so far revealed no EPSPs in expiratory internal intercostal nerve motoneurones under ketamine/xylazine anaesthesia (12 pairs tested, 3 animals). Direct, and possibly also specific indirect connections from EBSNs to thoracic motoneurones are therefore normally present in the rat, allowing comparison with newly formed connections of regenerating EBSN axons.